Generally, in a commercial electrostatographic reproduction apparatus (such as copier/duplicators, printers, or the like), a latent image charge pattern is formed on a uniformly charged photoconductive or dielectric member. Pigmented marking particles (toner) are attracted to the latent image charge pattern to develop such image on the dielectric member. A receiver member, such as paper, is then brought into contact with the dielectric member and an electric field applied to transfer the marking particle developed image to the receiver member from the dielectric member. After transfer, the receiver member bearing the transferred image is transported away from the dielectric member and the image is fixed or fused to the receiver member by heat and/or pressure to form a permanent reproduction thereon.
It is a common practice with an image forming apparatus to use an image transferring device of the type electrostatically transferring a toner image formed on an image carrier, or photoconductive element, to a sheet carried on a transfer belt to which an electric field opposite in polarity to the toner image is applied, and a separating device for separating the sheet from the photoconductive element. The devices of the type described usually include an arrangement for applying a transfer bias to the transfer belt. For example, an electrode member is connected to a high-tension power source and held in contact with the rear of the belt at an image transfer position. Such an arrangement, or so-called contact type transfer and separation arrangement, is advantageous over one which relies on a corona charge since it does not produce harmful ozone and can operate with a low voltage.
Electrostatic brush (ESB) cleaners have successfully cleaned belt photoreceptors with a combination of mechanical and electrostatic forces. Electrostatic forces are generated when charged particles enter an electric field created between the biased brush fibers and the grounded conductive layer within, the photoreceptor belt. It is desired to clean other surfaces, such as transfer belts, that do not have a conductive layer that can be grounded. In order to clean such surfaces, the belt is typically wrapped around a conductive roller. The size of the roller and the amount of wrap must be such that the entire brush interference to the belt is located over the roller. This requirement for creation of the electric field results in space limitations due to large rollers and belt tracking issues if multiple brushes and backer rollers are needed.
Today, in electrostatic marking systems, the marking apparatus is often smaller and more compact. Any size reduction in components is desirable since less space is occupied in component crammed apparatuses. When transfer belts are used in lieu of corotron transfer means, large conductive grounded rollers upon which these belts travel have been used. These rollers, while necessary and efficient, take up a large amount of space and add significant cost to the system.